This invention pertains to material handling, and more particularly to assembling a stack of flat sheet-like articles from a serial stream of such articles. The present invention has particular applicability in the newspaper industry and is intended for assembling a stack of newspapers from a predetermined counted number of newspapers advancing in a serial stream, and thereafter delivering the assembled stack to one or more conveyors. The stacks can thereafter be bound and shipped to the vendors as is the common practice in the newspaper industry, or otherwise handled.
Modern printing presses are capable of delivering completely finished newspapers at a rate approximating 90,000 newspapers per hour. The newspapers are delivered from the press on a conveyor in a serial stream. Vertical stacks of horizontal newspapers are immediately assembled from the serial stream from the press conveyor, and it is highly desirable to provide a stack assembling apparatus capable of operating at speeds equivalent to the maximum speed of the printing press. If the stack assembling apparatus is incapable of operating at the higher press speed, which is the case of many prior art machines, conveyor diverting equipment must be utilized in conjunction with plural stack assembling machines. Of course, it is desirable to avoid the additional expense of diverting equipment and stack assembling machines if possible.
Stack assembling machines are well known and have been utilized in the newspaper industry for many decades. Examples of prior art stack assembling machines are U.S. Pat. Nos. 3,599,807; 3,306,173; 3,083,014; 3,033,564; 3,088,604; 2,925,271; 2,884,246; 2,853,298; 2,815,210; 2,805,757; 2,795,420; 2,793,857; 2,788,131; 2,769,378; 2,733,064; 2,699,942; 2,697,602; 2,254,291; 2,205,767; 2,069,397; 1,586,544; 997,201; and 964,166.
In general, deficiencies in the prior art stack assembling machines reside primarily in an inability to operate accurately and reliably at speeds commensurate with modern high-speed printing presses. Many of the prior art stack assembling machines require elaborate and complicated mechanisms to perform the desired functions. Such elaborate mechanisms tend to decrease the reliability of operation when operated at increased speeds, although many prior stack assembling machines operate relatively satisfactorily at the lower press speeds typical of older printing presses. Attempts to increase the speed of such prior art stack assembling machines cause numerous problems including premature mechanical failure, an inability to form stacks of good integrity and shape, a tendency to damage certain newspapers during assembly of the stack, and an inability to accurately count predetermined numbers of newspapers into each stack. Many prior art stack assembling machines are capable of delivering the stacks of newspapers in only a single direction after the stacks have been assembled. Most newspaper printing operations in North and South America have been designed to receive the stacks of newspapers in a direction perpendicular to the supplied stream of newspapers from the printing press. In Europe and Asia, most newspaper printing operations require that the stacks be delivered parallel to the supplied stream of newspapers from the printing press. With these diverse requirements, two distinct types of stack handling machines have previously been required because the structure of most prior stack assembling machines could not be readily adapted to deliver the stacks from the perpendicular direction to the parallel direction, or vice versa. Other problems of prior art stack assembling machines are known to those involved in this field, and such problems and deficiencies will become more readily appreciated in view of the significant improvements available from the present invention.